Chemotherapy Treatment Frequency and Dosing Treatment schedules for chemotherapy vary widely. How often and how long you get chemotherapy depends upon: Your type of cancers and how advanced it is The goals of treatment The kind of chemotherapy drug or drugs How the body reacts to chemotherapy You might receive chemotherapy in cycles. A cycle is a period of chemotherapy treatment accompanied by an interval of rest. For instance, you may receive a week of chemotherapy accompanied by 3 weeks of rest. These 4 weeks make up one cycle. The rest period gives your body an opportunity to rebuild new healthy cells to replace those damaged by treatment.Jorg Hausleiter, M.D., of the Deutsches Herzzentrum Munchen, Klinik an der Technischen Universitat Munchen in Munich, Germany, and his study group investigated the magnitude of patient radiation exposure of CCTA in daily practice, factors contributing to this radiation dose and the use of well-known strategies that could decrease radiation dose. Their International Prospective Multicenter Research On Radiation Dose Estimates Of Cardiac CT Angiography In Daily Practice, referred to as Security I for brief, involved 1,965 patients undergoing CCTA between February and December 2007 at 21 university hospitals and 29 community hospitals. Radiation was measured as dosage length product which the researchers said in a press release may be the best way to find out how much radiation an individual is subjected to by the complete CT scan process.